Elastic anomaly of heavy fermion systems in a crystalline field II

An elastic anomaly, observed in the heavy Fermi liquid state of Ce alloys (for example, CeCu_6 and CeTe), is analyzed by using the infinite-U Anderson lattice model. Four atomic energy levels are assumed for f-electrons. Two of them are mutually degenerate. A small crystalline splitting 2 Delta is assumed between two energy levels. Fourfold degenerate conduction bands are also considered. We solve the model using the mean field approximation to slave bosons and the renormalized elastic constant is calculated. The temperature dependence of the constant shows the downward dip. The result is compared with the experimental data of CeTe.